ON THE PHYSIOLOGY OF THE LUNGS AND AIR-TUBES. 413 
experiments further, it was found that the irritability was only 
exhausted for a time; and on waiting two or three minutes 
between each application of the galvanism, the liquid was raised 
again and again for upwards of an hour; at first to the extent 
of one or two inches, but afterwards to a gradually diminishing 
extent, until all effect ceased. So, too, although no effect ensued 
immediately after inflating the lung, yet on waiting a minute or 
two the contraction took place, only diminished in degree by 
the compressed state of the air, which required more contractile 
force to move it. The fall on interrupting the current was 
pretty rapid, the fluid recovering its level in from ten to twenty 
seconds. 
3. Several trials were made to compare the contractility of 
the smaller and the larger bronchial tubes respectively. When 
the galvanism was passed along only the margins of the lobes, 
scarcely any contraction ensued. When passed from the margin 
to the middle of the lobes the column rose two or three tenths 
and soon subsided. When passed across a lobe, at right angles 
with the chief tubes, the rise was from two to four tenths. But 
the greatest amount of contraction was caused by passing the 
current from the margins of the lobes to the larger tubes, or 
across the direction of these tubes, especially near the bifurca- 
tion of the trachea. The rise produced by galvanising these 
portions could be also renewed at intervals for a period much 
longer than in other parts. 
4, The preceding experiments were all made on the lungs re- 
moved from the body immediately after death. I tried to obtain 
the same results with the lungs in the body; but it was not easy 
to galvanise the lungs without affecting the muscles of the chest, 
the contractions of which might interfere with the results. 
The expedient adopted was, immediately on the death of the 
animal to adapt the dynameter to the trachea; then to open 
the chest and break back the ribs, and having separated the 
lungs, to pass between them and the walls of the chest a piece of 
oiled cloth, and then to apply the galvanic wires to different parts 
of the lungs. This experiment gave less distinct results than 
when the lungs were removed from the body: It was repeated 
five times ; but it will be sufficient to describe one instance in 
which the galvanism was tried on the par vagum as well as on 
the lungs themselves. A large dog was pithed, and the dyna- 
meter adapted to the trachea. On opening the chest, the col- 
lapse of the lungs caused the fluid to rise three inches. The vagi 
being exposed in the neck, one was pinched ; it caused no effect 
on the dynameter. The other vagus was then galvanised across 
and along a portion of it; no effect followed in the bronchial 
